Ancient Chinese medical remedy offers promise for cancer patients

Two bioengineering researchers at the University of Washington have
discovered a promising potential treatment for cancer among the
ancient arts of Chinese folk medicine.

Two bioengineering researchers at the University of Washington have
discovered a promising potential treatment for cancer among the
ancient arts of Chinese folk medicine.

Research Professor Henry Lai and assistant research Professor
Narendra Singh have exploited the chemical properties of a wormwood
derivative to target breast cancer cells, with surprisingly
effective results. A study in the latest issue of the journal Life
Sciences describes how the derivative killed virtually all human
breast cancer cells exposed to it within 16 hours.

"Not only does it appear to be effective, but it's very
selective,"​ Lai said. "It's highly toxic to the cancer
cells, but has a marginal impact on normal breast cells."​

The compound, artemisinin, isn't new. It apparently was
extracted from the plant Artemesia annua L., commonly known as
wormwood, thousands of years ago by the Chinese, who used it to
combat malaria. However, the treatment was lost over time.
Artemisinin was rediscovered during an archaeological dig in the
1970s that unearthed recipes for ancient medical remedies, and has
become widely used in modern Asia and Africa to fight the
mosquito-borne disease.

The compound helps control malaria because it reacts with the
high iron concentrations found in the malaria parasite. When
artemisinin comes into contact with iron, a chemical reaction
ensues, spawning charged atoms that chemists call "free radicals."
The free radicals attack cell membranes, breaking them apart and
killing the single-cell parasite.

About seven years ago, Lai began to hypothesise that the process
might work with cancer, too.

"Cancer cells need a lot of iron to replicate DNA when they
divide,"​ Lai explained. "As a result, cancer cells have much
higher iron concentrations than normal cells. When we began to
understand how artemisinin worked, I started wondering if we could
use that knowledge to target cancer cells."​

Lai devised a potential method and began to look for funding,
obtaining a grant from the Breast Cancer Fund in San Francisco.
Meanwhile, the UW patented his idea.

The thrust of the idea, according to Lai and Singh, was to pump
up the cancer cells with maximum iron concentrations, then
introduce artemisinin to selectively kill the cancer. To
accommodate a rate of iron intake greater than normal cells, cancer
cell surfaces feature greater concentrations of transferrin
receptors - cellular pathways that allow iron into a cell. Breast
cancer cells are no exception. They have five to 15 times more
transferrin receptors on their surface than normal breast
cells.

In the current study, the researchers subjected sets of breast
cancer cells and normal breast cells to doses of holotransferrin
(which binds with transferrin receptors to transport iron into
cells), dihydroartemisinin (a more water-soluble form of
artemisinin) and a combination of both compounds. Cells exposed to
just one of the compounds showed no appreciable effect. Normal
breast cells, exposed to both compounds, exhibited a minimal
effect. But the response by cancer cells when hit with first
holotransferrin, then dihydroartemisinin, was dramatic.

After eight hours, just 25 per cent of the cancer cells
remained. By the time 16 hours had passed, nearly all the cells
were dead. An earlier study involving leukemia cells yielded even
more impressive results. Those cells were eliminated within eight
hours. A possible explanation might be the level of iron in the
leukemia cells.

"They have one of the highest iron concentrations among
cancer cells,"​ Lai explained. "Leukemia cells can have more
than 1,000 times the concentration of iron that normal cells
have."​

The next step, according to Lai, is animal testing. Limited
tests have been done in that area. In an earlier study, a dog with
bone cancer so severe it couldn't walk made a complete recovery in
five days after receiving the treatment. But more rigorous testing
is needed.

If the process lives up to its early promise, it could
revolutionize the way some cancers are approached, Lai said. The
goal would be a treatment that could be taken orally, on an
outpatient basis.

"That would be very easy, and this could make that
possible,"​ Lai said. "The cost is another plus - at $2 a
dose, it's very cheap. And, with the millions of people who have
already taken artemisinin for malaria, we have a track record
showing that it's safe."​

Whatever happens, Lai said, a portion of the credit will have to
go to unknown medical practitioners, long gone now.

"The fascinating thing is that this was something the Chinese
used thousands of years ago,"​ he said. "We simply found a
different application."​